/* Control flow optimization code for GNU compiler.
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
-/* This file contains optimizer of the control flow. The main entrypoint is
+/* This file contains optimizer of the control flow. The main entry point is
cleanup_cfg. Following optimizations are performed:
- Unreachable blocks removal
- - Edge forwarding (edge to the forwarder block is forwarded to it's
+ - Edge forwarding (edge to the forwarder block is forwarded to its
successor. Simplification of the branch instruction is performed by
underlying infrastructure so branch can be converted to simplejump or
eliminated).
#include "tm.h"
#include "rtl.h"
#include "hard-reg-set.h"
-#include "basic-block.h"
+#include "regs.h"
#include "timevar.h"
#include "output.h"
#include "insn-config.h"
#include "params.h"
#include "tm_p.h"
#include "target.h"
-#include "regs.h"
+#include "cfglayout.h"
+#include "emit-rtl.h"
/* cleanup_cfg maintains following flags for each basic block. */
static int flow_find_cross_jump (int, basic_block, basic_block, rtx *, rtx *);
static bool insns_match_p (int, rtx, rtx);
-static bool tail_recursion_label_p (rtx);
static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block);
static void merge_blocks_move_successor_nojumps (basic_block, basic_block);
static bool try_optimize_cfg (int);
static void notice_new_block (basic_block);
static void update_forwarder_flag (basic_block);
static int mentions_nonequal_regs (rtx *, void *);
+static void merge_memattrs (rtx, rtx);
\f
/* Set flags for newly created block. */
basic_block jump_block, jump_dest_block, cbranch_dest_block;
edge cbranch_jump_edge, cbranch_fallthru_edge;
rtx cbranch_insn;
- rtx insn, next;
- rtx end;
/* Verify that there are exactly two successors. */
- if (!cbranch_block->succ
- || !cbranch_block->succ->succ_next
- || cbranch_block->succ->succ_next->succ_next)
+ if (EDGE_COUNT (cbranch_block->succs) != 2)
return false;
/* Verify that we've got a normal conditional branch at the end
be the last block in the function, and must contain just the
unconditional jump. */
jump_block = cbranch_fallthru_edge->dest;
- if (jump_block->pred->pred_next
+ if (!single_pred_p (jump_block)
|| jump_block->next_bb == EXIT_BLOCK_PTR
|| !FORWARDER_BLOCK_P (jump_block))
return false;
- jump_dest_block = jump_block->succ->dest;
+ jump_dest_block = single_succ (jump_block);
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (jump_block) != BB_PARTITION (jump_dest_block)
+ || (cbranch_jump_edge->flags & EDGE_CROSSING))
+ return false;
/* The conditional branch must target the block after the
unconditional branch. */
cbranch_dest_block = cbranch_jump_edge->dest;
- if (!can_fallthru (jump_block, cbranch_dest_block))
+ if (cbranch_dest_block == EXIT_BLOCK_PTR
+ || !can_fallthru (jump_block, cbranch_dest_block))
return false;
/* Invert the conditional branch. */
if (!invert_jump (cbranch_insn, block_label (jump_dest_block), 0))
return false;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Simplifying condjump %i around jump %i\n",
+ if (dump_file)
+ fprintf (dump_file, "Simplifying condjump %i around jump %i\n",
INSN_UID (cbranch_insn), INSN_UID (BB_END (jump_block)));
/* Success. Update the CFG to match. Note that after this point
cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU;
update_br_prob_note (cbranch_block);
- end = BB_END (jump_block);
- /* Deleting a block may produce unreachable code warning even when we are
- not deleting anything live. Suppress it by moving all the line number
- notes out of the block. */
- for (insn = BB_HEAD (jump_block); insn != NEXT_INSN (BB_END (jump_block));
- insn = next)
- {
- next = NEXT_INSN (insn);
- if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) > 0)
- {
- if (insn == BB_END (jump_block))
- {
- BB_END (jump_block) = PREV_INSN (insn);
- if (insn == end)
- break;
- }
- reorder_insns_nobb (insn, insn, end);
- end = insn;
- }
- }
/* Delete the block with the unconditional jump, and clean up the mess. */
delete_basic_block (jump_block);
tidy_fallthru_edge (cbranch_jump_edge);
+ update_forwarder_flag (cbranch_block);
return true;
}
rtx set1, set2, cond1, cond2, insn;
enum rtx_code code1, code2, reversed_code2;
bool reverse1 = false;
- int i;
+ unsigned i;
regset nonequal;
bool failed = false;
+ reg_set_iterator rsi;
if (BB_FLAGS (b) & BB_NONTHREADABLE_BLOCK)
return NULL;
/* At the moment, we do handle only conditional jumps, but later we may
want to extend this code to tablejumps and others. */
- if (!e->src->succ->succ_next || e->src->succ->succ_next->succ_next)
+ if (EDGE_COUNT (e->src->succs) != 2)
return NULL;
- if (!b->succ || !b->succ->succ_next || b->succ->succ_next->succ_next)
+ if (EDGE_COUNT (b->succs) != 2)
{
BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK);
return NULL;
return NULL;
}
- cselib_init ();
+ cselib_init (false);
/* First process all values computed in the source basic block. */
- for (insn = NEXT_INSN (BB_HEAD (e->src)); insn != NEXT_INSN (BB_END (e->src));
+ for (insn = NEXT_INSN (BB_HEAD (e->src));
+ insn != NEXT_INSN (BB_END (e->src));
insn = NEXT_INSN (insn))
if (INSN_P (insn))
cselib_process_insn (insn);
- nonequal = BITMAP_XMALLOC();
+ nonequal = BITMAP_ALLOC (NULL);
CLEAR_REG_SET (nonequal);
/* Now assume that we've continued by the edge E to B and continue
processing as if it were same basic block.
Our goal is to prove that whole block is an NOOP. */
- for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b)) && !failed;
+ for (insn = NEXT_INSN (BB_HEAD (b));
+ insn != NEXT_INSN (BB_END (b)) && !failed;
insn = NEXT_INSN (insn))
{
if (INSN_P (insn))
if (GET_CODE (pat) == PARALLEL)
{
- for (i = 0; i < XVECLEN (pat, 0); i++)
+ for (i = 0; i < (unsigned)XVECLEN (pat, 0); i++)
failed |= mark_effect (XVECEXP (pat, 0, i), nonequal);
}
else
if (mode & CLEANUP_UPDATE_LIFE)
AND_REG_SET (nonequal, b->global_live_at_end);
- EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, goto failed_exit;);
+ EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, rsi)
+ goto failed_exit;
- BITMAP_XFREE (nonequal);
+ BITMAP_FREE (nonequal);
cselib_finish ();
if ((comparison_dominates_p (code1, code2) != 0)
!= (XEXP (SET_SRC (set2), 1) == pc_rtx))
return FALLTHRU_EDGE (b);
failed_exit:
- BITMAP_XFREE (nonequal);
+ BITMAP_FREE (nonequal);
cselib_finish ();
return NULL;
}
try_forward_edges (int mode, basic_block b)
{
bool changed = false;
- edge e, next, *threaded_edges = NULL;
+ edge_iterator ei;
+ edge e, *threaded_edges = NULL;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really m
+ ust be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX))
+ return false;
- for (e = b->succ; e; e = next)
+ for (ei = ei_start (b->succs); (e = ei_safe_edge (ei)); )
{
basic_block target, first;
int counter;
int nthreaded_edges = 0;
bool may_thread = first_pass | (b->flags & BB_DIRTY);
- next = e->succ_next;
-
/* Skip complex edges because we don't know how to update them.
Still handle fallthru edges, as we can succeed to forward fallthru
edge to the same place as the branch edge of conditional branch
and turn conditional branch to an unconditional branch. */
if (e->flags & EDGE_COMPLEX)
- continue;
+ {
+ ei_next (&ei);
+ continue;
+ }
target = first = e->dest;
counter = 0;
+ /* If we are partitioning hot/cold basic_blocks, we don't want to mess
+ up jumps that cross between hot/cold sections.
+
+ Basic block partitioning may result in some jumps that appear
+ to be optimizable (or blocks that appear to be mergeable), but which
+ really must be left untouched (they are required to make it safely
+ across partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete
+ details. */
+
+ if (first != EXIT_BLOCK_PTR
+ && find_reg_note (BB_END (first), REG_CROSSING_JUMP, NULL_RTX))
+ return false;
+
while (counter < n_basic_blocks)
{
basic_block new_target = NULL;
may_thread |= target->flags & BB_DIRTY;
if (FORWARDER_BLOCK_P (target)
- && target->succ->dest != EXIT_BLOCK_PTR)
+ && !(single_succ_edge (target)->flags & EDGE_CROSSING)
+ && single_succ (target) != EXIT_BLOCK_PTR)
{
/* Bypass trivial infinite loops. */
- if (target == target->succ->dest)
+ new_target = single_succ (target);
+ if (target == new_target)
counter = n_basic_blocks;
- new_target = target->succ->dest;
}
/* Allow to thread only over one edge at time to simplify updating
if (t->dest == b)
break;
- if (nthreaded_edges >= n_basic_blocks)
- abort ();
+ gcc_assert (nthreaded_edges < n_basic_blocks);
threaded_edges[nthreaded_edges++] = t;
new_target = t->dest;
For fallthru forwarders, the LOOP_BEG note must appear between
the header of block and CODE_LABEL of the loop, for non forwarders
it must appear before the JUMP_INSN. */
- if ((mode & CLEANUP_PRE_LOOP) && optimize)
+ if ((mode & CLEANUP_PRE_LOOP) && optimize && flag_loop_optimize)
{
- rtx insn = (target->succ->flags & EDGE_FALLTHRU
+ rtx insn = (EDGE_SUCC (target, 0)->flags & EDGE_FALLTHRU
? BB_HEAD (target) : prev_nonnote_insn (BB_END (target)));
- if (GET_CODE (insn) != NOTE)
+ if (!NOTE_P (insn))
insn = NEXT_INSN (insn);
- for (; insn && GET_CODE (insn) != CODE_LABEL && !INSN_P (insn);
+ for (; insn && !LABEL_P (insn) && !INSN_P (insn);
insn = NEXT_INSN (insn))
- if (GET_CODE (insn) == NOTE
+ if (NOTE_P (insn)
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
break;
- if (GET_CODE (insn) == NOTE)
+ if (NOTE_P (insn))
break;
/* Do not clean up branches to just past the end of a loop
recognition of some patterns. */
insn = PREV_INSN (BB_HEAD (target));
- if (insn && GET_CODE (insn) == NOTE
+ if (insn && NOTE_P (insn)
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
break;
}
if (counter >= n_basic_blocks)
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Infinite loop in BB %i.\n",
+ if (dump_file)
+ fprintf (dump_file, "Infinite loop in BB %i.\n",
target->index);
}
else if (target == first)
if (threaded && target != EXIT_BLOCK_PTR)
{
notice_new_block (redirect_edge_and_branch_force (e, target));
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Conditionals threaded.\n");
+ if (dump_file)
+ fprintf (dump_file, "Conditionals threaded.\n");
}
else if (!redirect_edge_and_branch (e, target))
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Forwarding edge %i->%i to %i failed.\n",
b->index, e->dest->index, target->index);
+ ei_next (&ei);
continue;
}
{
edge t;
- first->count -= edge_count;
- if (first->count < 0)
- first->count = 0;
- first->frequency -= edge_frequency;
- if (first->frequency < 0)
- first->frequency = 0;
- if (first->succ->succ_next)
+ if (!single_succ_p (first))
{
- edge e;
- int prob;
- if (n >= nthreaded_edges)
- abort ();
+ gcc_assert (n < nthreaded_edges);
t = threaded_edges [n++];
- if (t->src != first)
- abort ();
- if (first->frequency)
- prob = edge_frequency * REG_BR_PROB_BASE / first->frequency;
- else
- prob = 0;
- if (prob > t->probability)
- prob = t->probability;
- t->probability -= prob;
- prob = REG_BR_PROB_BASE - prob;
- if (prob <= 0)
- {
- first->succ->probability = REG_BR_PROB_BASE;
- first->succ->succ_next->probability = 0;
- }
- else
- for (e = first->succ; e; e = e->succ_next)
- e->probability = ((e->probability * REG_BR_PROB_BASE)
- / (double) prob);
+ gcc_assert (t->src == first);
+ update_bb_profile_for_threading (first, edge_frequency,
+ edge_count, t);
update_br_prob_note (first);
}
else
{
+ first->count -= edge_count;
+ if (first->count < 0)
+ first->count = 0;
+ first->frequency -= edge_frequency;
+ if (first->frequency < 0)
+ first->frequency = 0;
/* It is possible that as the result of
threading we've removed edge as it is
threaded to the fallthru edge. Avoid
if (n < nthreaded_edges
&& first == threaded_edges [n]->src)
n++;
- t = first->succ;
+ t = single_succ_edge (first);
}
t->count -= edge_count;
while (first != target);
changed = true;
+ continue;
}
+ ei_next (&ei);
}
if (threaded_edges)
return changed;
}
\f
-/* Return true if LABEL is used for tail recursion. */
-
-static bool
-tail_recursion_label_p (rtx label)
-{
- rtx x;
-
- for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
- if (label == XEXP (x, 0))
- return true;
-
- return false;
-}
/* Blocks A and B are to be merged into a single block. A has no incoming
fallthru edge, so it can be moved before B without adding or modifying
merge_blocks_move_predecessor_nojumps (basic_block a, basic_block b)
{
rtx barrier;
+ bool only_notes;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (a) != BB_PARTITION (b))
+ return;
barrier = next_nonnote_insn (BB_END (a));
- if (GET_CODE (barrier) != BARRIER)
- abort ();
+ gcc_assert (BARRIER_P (barrier));
delete_insn (barrier);
/* Move block and loop notes out of the chain so that we do not
and adjust the block trees appropriately. Even better would be to have
a tighter connection between block trees and rtl so that this is not
necessary. */
- if (squeeze_notes (&BB_HEAD (a), &BB_END (a)))
- abort ();
+ only_notes = squeeze_notes (&BB_HEAD (a), &BB_END (a));
+ gcc_assert (!only_notes);
/* Scramble the insn chain. */
if (BB_END (a) != PREV_INSN (BB_HEAD (b)))
reorder_insns_nobb (BB_HEAD (a), BB_END (a), PREV_INSN (BB_HEAD (b)));
a->flags |= BB_DIRTY;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
+ if (dump_file)
+ fprintf (dump_file, "Moved block %d before %d and merged.\n",
a->index, b->index);
/* Swap the records for the two blocks around. */
{
rtx barrier, real_b_end;
rtx label, table;
+ bool only_notes;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (a) != BB_PARTITION (b))
+ return;
real_b_end = BB_END (b);
/* There had better have been a barrier there. Delete it. */
barrier = NEXT_INSN (BB_END (b));
- if (barrier && GET_CODE (barrier) == BARRIER)
+ if (barrier && BARRIER_P (barrier))
delete_insn (barrier);
/* Move block and loop notes out of the chain so that we do not
and adjust the block trees appropriately. Even better would be to have
a tighter connection between block trees and rtl so that this is not
necessary. */
- if (squeeze_notes (&BB_HEAD (b), &BB_END (b)))
- abort ();
+ only_notes = squeeze_notes (&BB_HEAD (b), &BB_END (b));
+ gcc_assert (!only_notes);
+
/* Scramble the insn chain. */
reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a));
/* Restore the real end of b. */
BB_END (b) = real_b_end;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
+ if (dump_file)
+ fprintf (dump_file, "Moved block %d after %d and merged.\n",
b->index, a->index);
/* Now blocks A and B are contiguous. Merge them. */
merge_blocks_move (edge e, basic_block b, basic_block c, int mode)
{
basic_block next;
- /* If C has a tail recursion label, do not merge. There is no
- edge recorded from the call_placeholder back to this label, as
- that would make optimize_sibling_and_tail_recursive_calls more
- complex for no gain. */
- if ((mode & CLEANUP_PRE_SIBCALL)
- && GET_CODE (BB_HEAD (c)) == CODE_LABEL
- && tail_recursion_label_p (BB_HEAD (c)))
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (b) != BB_PARTITION (c))
return NULL;
+
+
/* If B has a fallthru edge to C, no need to move anything. */
if (e->flags & EDGE_FALLTHRU)
merge_blocks (b, c);
update_forwarder_flag (b);
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
+ if (dump_file)
+ fprintf (dump_file, "Merged %d and %d without moving.\n",
b_index, c_index);
return b->prev_bb == ENTRY_BLOCK_PTR ? b : b->prev_bb;
edge tmp_edge, b_fallthru_edge;
bool c_has_outgoing_fallthru;
bool b_has_incoming_fallthru;
+ edge_iterator ei;
/* Avoid overactive code motion, as the forwarder blocks should be
eliminated by edge redirection instead. One exception might have
and loop notes. This is done by squeezing out all the notes
and leaving them there to lie. Not ideal, but functional. */
- for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
+ FOR_EACH_EDGE (tmp_edge, ei, c->succs)
if (tmp_edge->flags & EDGE_FALLTHRU)
break;
c_has_outgoing_fallthru = (tmp_edge != NULL);
- for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
+ FOR_EACH_EDGE (tmp_edge, ei, b->preds)
if (tmp_edge->flags & EDGE_FALLTHRU)
break;
}
\f
+/* Removes the memory attributes of MEM expression
+ if they are not equal. */
+
+void
+merge_memattrs (rtx x, rtx y)
+{
+ int i;
+ int j;
+ enum rtx_code code;
+ const char *fmt;
+
+ if (x == y)
+ return;
+ if (x == 0 || y == 0)
+ return;
+
+ code = GET_CODE (x);
+
+ if (code != GET_CODE (y))
+ return;
+
+ if (GET_MODE (x) != GET_MODE (y))
+ return;
+
+ if (code == MEM && MEM_ATTRS (x) != MEM_ATTRS (y))
+ {
+ if (! MEM_ATTRS (x))
+ MEM_ATTRS (y) = 0;
+ else if (! MEM_ATTRS (y))
+ MEM_ATTRS (x) = 0;
+ else
+ {
+ rtx mem_size;
+
+ if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y))
+ {
+ set_mem_alias_set (x, 0);
+ set_mem_alias_set (y, 0);
+ }
+
+ if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y)))
+ {
+ set_mem_expr (x, 0);
+ set_mem_expr (y, 0);
+ set_mem_offset (x, 0);
+ set_mem_offset (y, 0);
+ }
+ else if (MEM_OFFSET (x) != MEM_OFFSET (y))
+ {
+ set_mem_offset (x, 0);
+ set_mem_offset (y, 0);
+ }
+
+ if (!MEM_SIZE (x))
+ mem_size = NULL_RTX;
+ else if (!MEM_SIZE (y))
+ mem_size = NULL_RTX;
+ else
+ mem_size = GEN_INT (MAX (INTVAL (MEM_SIZE (x)),
+ INTVAL (MEM_SIZE (y))));
+ set_mem_size (x, mem_size);
+ set_mem_size (y, mem_size);
+
+ set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y)));
+ set_mem_align (y, MEM_ALIGN (x));
+ }
+ }
+
+ fmt = GET_RTX_FORMAT (code);
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ switch (fmt[i])
+ {
+ case 'E':
+ /* Two vectors must have the same length. */
+ if (XVECLEN (x, i) != XVECLEN (y, i))
+ return;
+
+ for (j = 0; j < XVECLEN (x, i); j++)
+ merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j));
+
+ break;
+
+ case 'e':
+ merge_memattrs (XEXP (x, i), XEXP (y, i));
+ }
+ }
+ return;
+}
+
+
/* Return true if I1 and I2 are equivalent and thus can be crossjumped. */
static bool
??? We take the simple route for now and assume that if they're
equal, they were constructed identically. */
- if (GET_CODE (i1) == CALL_INSN
+ if (CALL_P (i1)
&& (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
CALL_INSN_FUNCTION_USAGE (i2))
|| SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)))
if (!insns_match_p (mode, i1, i2))
break;
+ merge_memattrs (i1, i2);
+
/* Don't begin a cross-jump with a NOTE insn. */
if (INSN_P (i1))
{
while (last1 != BB_HEAD (bb1) && !INSN_P (PREV_INSN (last1)))
last1 = PREV_INSN (last1);
- if (last1 != BB_HEAD (bb1) && GET_CODE (PREV_INSN (last1)) == CODE_LABEL)
+ if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1)))
last1 = PREV_INSN (last1);
while (last2 != BB_HEAD (bb2) && !INSN_P (PREV_INSN (last2)))
last2 = PREV_INSN (last2);
- if (last2 != BB_HEAD (bb2) && GET_CODE (PREV_INSN (last2)) == CODE_LABEL)
+ if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2)))
last2 = PREV_INSN (last2);
*f1 = last1;
int nehedges1 = 0, nehedges2 = 0;
edge fallthru1 = 0, fallthru2 = 0;
edge e1, e2;
+ edge_iterator ei;
/* If BB1 has only one successor, we may be looking at either an
unconditional jump, or a fake edge to exit. */
- if (bb1->succ && !bb1->succ->succ_next
- && (bb1->succ->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0
- && (GET_CODE (BB_END (bb1)) != JUMP_INSN || simplejump_p (BB_END (bb1))))
- return (bb2->succ && !bb2->succ->succ_next
- && (bb2->succ->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0
- && (GET_CODE (BB_END (bb2)) != JUMP_INSN || simplejump_p (BB_END (bb2))));
+ if (single_succ_p (bb1)
+ && (single_succ_edge (bb1)->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0
+ && (!JUMP_P (BB_END (bb1)) || simplejump_p (BB_END (bb1))))
+ return (single_succ_p (bb2)
+ && (single_succ_edge (bb2)->flags
+ & (EDGE_COMPLEX | EDGE_FAKE)) == 0
+ && (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2))));
/* Match conditional jumps - this may get tricky when fallthru and branch
edges are crossed. */
- if (bb1->succ
- && bb1->succ->succ_next
- && !bb1->succ->succ_next->succ_next
+ if (EDGE_COUNT (bb1->succs) == 2
&& any_condjump_p (BB_END (bb1))
&& onlyjump_p (BB_END (bb1)))
{
rtx set1, set2, cond1, cond2;
enum rtx_code code1, code2;
- if (!bb2->succ
- || !bb2->succ->succ_next
- || bb2->succ->succ_next->succ_next
+ if (EDGE_COUNT (bb2->succs) != 2
|| !any_condjump_p (BB_END (bb2))
|| !onlyjump_p (BB_END (bb2)))
return false;
/* Get around possible forwarders on fallthru edges. Other cases
should be optimized out already. */
if (FORWARDER_BLOCK_P (f1->dest))
- f1 = f1->dest->succ;
+ f1 = single_succ_edge (f1->dest);
if (FORWARDER_BLOCK_P (f2->dest))
- f2 = f2->dest->succ;
+ f2 = single_succ_edge (f2->dest);
/* To simplify use of this function, return false if there are
unneeded forwarder blocks. These will get eliminated later
outcomes. */
if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2)
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
- "Outcomes of branch in bb %i and %i differs to much (%i %i)\n",
+ if (dump_file)
+ fprintf (dump_file,
+ "Outcomes of branch in bb %i and %i differ too much (%i %i)\n",
bb1->index, bb2->index, b1->probability, prob2);
return false;
}
}
- if (rtl_dump_file && match)
- fprintf (rtl_dump_file, "Conditionals in bb %i and %i match.\n",
+ if (dump_file && match)
+ fprintf (dump_file, "Conditionals in bb %i and %i match.\n",
bb1->index, bb2->index);
return match;
/* Generic case - we are seeing a computed jump, table jump or trapping
instruction. */
-#ifndef CASE_DROPS_THROUGH
/* Check whether there are tablejumps in the end of BB1 and BB2.
Return true if they are identical. */
{
/* The labels should never be the same rtx. If they really are same
the jump tables are same too. So disable crossjumping of blocks BB1
and BB2 because when deleting the common insns in the end of BB1
- by delete_block () the jump table would be deleted too. */
+ by delete_basic_block () the jump table would be deleted too. */
/* If LABEL2 is referenced in BB1->END do not do anything
because we would loose information when replacing
LABEL1 by LABEL2 and then LABEL2 by LABEL1 in BB1->END. */
for_each_rtx (&BB_END (bb1), replace_label, &rr);
match = insns_match_p (mode, BB_END (bb1), BB_END (bb2));
- if (rtl_dump_file && match)
- fprintf (rtl_dump_file,
+ if (dump_file && match)
+ fprintf (dump_file,
"Tablejumps in bb %i and %i match.\n",
bb1->index, bb2->index);
return false;
}
}
-#endif
/* First ensure that the instructions match. There may be many outgoing
edges so this test is generally cheaper. */
/* Search the outgoing edges, ensure that the counts do match, find possible
fallthru and exception handling edges since these needs more
validation. */
- for (e1 = bb1->succ, e2 = bb2->succ; e1 && e2;
- e1 = e1->succ_next, e2 = e2->succ_next)
+ if (EDGE_COUNT (bb1->succs) != EDGE_COUNT (bb2->succs))
+ return false;
+
+ FOR_EACH_EDGE (e1, ei, bb1->succs)
{
+ e2 = EDGE_SUCC (bb2, ei.index);
+
if (e1->flags & EDGE_EH)
nehedges1++;
}
/* If number of edges of various types does not match, fail. */
- if (e1 || e2
- || nehedges1 != nehedges2
+ if (nehedges1 != nehedges2
|| (fallthru1 != 0) != (fallthru2 != 0))
return false;
if (fallthru1)
{
basic_block d1 = (forwarder_block_p (fallthru1->dest)
- ? fallthru1->dest->succ->dest: fallthru1->dest);
+ ? single_succ (fallthru1->dest): fallthru1->dest);
basic_block d2 = (forwarder_block_p (fallthru2->dest)
- ? fallthru2->dest->succ->dest: fallthru2->dest);
+ ? single_succ (fallthru2->dest): fallthru2->dest);
if (d1 != d2)
return false;
basic_block redirect_to, redirect_from, to_remove;
rtx newpos1, newpos2;
edge s;
+ edge_iterator ei;
+
+ newpos1 = newpos2 = NULL_RTX;
+
+ /* If we have partitioned hot/cold basic blocks, it is a bad idea
+ to try this optimization.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (flag_reorder_blocks_and_partition && no_new_pseudos)
+ return false;
/* Search backward through forwarder blocks. We don't need to worry
about multiple entry or chained forwarders, as they will be optimized
away. We do this to look past the unconditional jump following a
conditional jump that is required due to the current CFG shape. */
- if (src1->pred
- && !src1->pred->pred_next
+ if (single_pred_p (src1)
&& FORWARDER_BLOCK_P (src1))
- e1 = src1->pred, src1 = e1->src;
+ e1 = single_pred_edge (src1), src1 = e1->src;
- if (src2->pred
- && !src2->pred->pred_next
+ if (single_pred_p (src2)
&& FORWARDER_BLOCK_P (src2))
- e2 = src2->pred, src2 = e2->src;
+ e2 = single_pred_edge (src2), src2 = e2->src;
/* Nothing to do if we reach ENTRY, or a common source block. */
if (src1 == ENTRY_BLOCK_PTR || src2 == ENTRY_BLOCK_PTR)
/* Seeing more than 1 forwarder blocks would confuse us later... */
if (FORWARDER_BLOCK_P (e1->dest)
- && FORWARDER_BLOCK_P (e1->dest->succ->dest))
+ && FORWARDER_BLOCK_P (single_succ (e1->dest)))
return false;
if (FORWARDER_BLOCK_P (e2->dest)
- && FORWARDER_BLOCK_P (e2->dest->succ->dest))
+ && FORWARDER_BLOCK_P (single_succ (e2->dest)))
return false;
/* Likewise with dead code (possibly newly created by the other optimizations
of cfg_cleanup). */
- if (!src1->pred || !src2->pred)
+ if (EDGE_COUNT (src1->preds) == 0 || EDGE_COUNT (src2->preds) == 0)
return false;
/* Look for the common insn sequence, part the first ... */
/* ... and part the second. */
nmatch = flow_find_cross_jump (mode, src1, src2, &newpos1, &newpos2);
- if (!nmatch)
+
+ /* Don't proceed with the crossjump unless we found a sufficient number
+ of matching instructions or the 'from' block was totally matched
+ (such that its predecessors will hopefully be redirected and the
+ block removed). */
+ if ((nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
+ && (newpos1 != BB_HEAD (src1)))
return false;
-#ifndef CASE_DROPS_THROUGH
/* Here we know that the insns in the end of SRC1 which are common with SRC2
will be deleted.
If we have tablejumps in the end of SRC1 and SRC2
}
}
}
-#endif
/* Avoid splitting if possible. */
if (newpos2 == BB_HEAD (src2))
redirect_to = src2;
else
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Splitting bb %i before %i insns\n",
+ if (dump_file)
+ fprintf (dump_file, "Splitting bb %i before %i insns\n",
src2->index, nmatch);
redirect_to = split_block (src2, PREV_INSN (newpos2))->dest;
}
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Cross jumping from bb %i to bb %i; %i common insns\n",
src1->index, src2->index, nmatch);
redirect_to->flags |= BB_DIRTY;
/* Recompute the frequencies and counts of outgoing edges. */
- for (s = redirect_to->succ; s; s = s->succ_next)
+ FOR_EACH_EDGE (s, ei, redirect_to->succs)
{
edge s2;
+ edge_iterator ei;
basic_block d = s->dest;
if (FORWARDER_BLOCK_P (d))
- d = d->succ->dest;
+ d = single_succ (d);
- for (s2 = src1->succ; ; s2 = s2->succ_next)
+ FOR_EACH_EDGE (s2, ei, src1->succs)
{
basic_block d2 = s2->dest;
if (FORWARDER_BLOCK_P (d2))
- d2 = d2->succ->dest;
+ d2 = single_succ (d2);
if (d == d2)
break;
}
into infinite loop. */
if (FORWARDER_BLOCK_P (s->dest))
{
- s->dest->succ->count += s2->count;
+ single_succ_edge (s->dest)->count += s2->count;
s->dest->count += s2->count;
s->dest->frequency += EDGE_FREQUENCY (s);
}
if (FORWARDER_BLOCK_P (s2->dest))
{
- s2->dest->succ->count -= s2->count;
- if (s2->dest->succ->count < 0)
- s2->dest->succ->count = 0;
+ single_succ_edge (s2->dest)->count -= s2->count;
+ if (single_succ_edge (s2->dest)->count < 0)
+ single_succ_edge (s2->dest)->count = 0;
s2->dest->count -= s2->count;
s2->dest->frequency -= EDGE_FREQUENCY (s);
if (s2->dest->frequency < 0)
/* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */
/* Skip possible basic block header. */
- if (GET_CODE (newpos1) == CODE_LABEL)
+ if (LABEL_P (newpos1))
newpos1 = NEXT_INSN (newpos1);
- if (GET_CODE (newpos1) == NOTE)
+ if (NOTE_P (newpos1))
newpos1 = NEXT_INSN (newpos1);
redirect_from = split_block (src1, PREV_INSN (newpos1))->src;
- to_remove = redirect_from->succ->dest;
+ to_remove = single_succ (redirect_from);
- redirect_edge_and_branch_force (redirect_from->succ, redirect_to);
+ redirect_edge_and_branch_force (single_succ_edge (redirect_from), redirect_to);
delete_basic_block (to_remove);
update_forwarder_flag (redirect_from);
+ if (redirect_to != src2)
+ update_forwarder_flag (src2);
return true;
}
static bool
try_crossjump_bb (int mode, basic_block bb)
{
- edge e, e2, nexte2, nexte, fallthru;
+ edge e, e2, fallthru;
bool changed;
- int n = 0, max;
+ unsigned max, ix, ix2;
+ basic_block ev, ev2;
+ edge_iterator ei;
/* Nothing to do if there is not at least two incoming edges. */
- if (!bb->pred || !bb->pred->pred_next)
+ if (EDGE_COUNT (bb->preds) < 2)
+ return false;
+
+ /* Don't crossjump if this block ends in a computed jump,
+ unless we are optimizing for size. */
+ if (!optimize_size
+ && bb != EXIT_BLOCK_PTR
+ && computed_jump_p (BB_END (bb)))
+ return false;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (EDGE_PRED (bb, 0)->src) !=
+ BB_PARTITION (EDGE_PRED (bb, 1)->src)
+ || (EDGE_PRED (bb, 0)->flags & EDGE_CROSSING))
return false;
/* It is always cheapest to redirect a block that ends in a branch to
program. We'll try that combination first. */
fallthru = NULL;
max = PARAM_VALUE (PARAM_MAX_CROSSJUMP_EDGES);
- for (e = bb->pred; e ; e = e->pred_next, n++)
+
+ if (EDGE_COUNT (bb->preds) > max)
+ return false;
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
{
if (e->flags & EDGE_FALLTHRU)
- fallthru = e;
- if (n > max)
- return false;
+ fallthru = e;
}
changed = false;
- for (e = bb->pred; e; e = nexte)
+ for (ix = 0, ev = bb; ix < EDGE_COUNT (ev->preds); )
{
- nexte = e->pred_next;
+ e = EDGE_PRED (ev, ix);
+ ix++;
/* As noted above, first try with the fallthru predecessor. */
if (fallthru)
if (try_crossjump_to_edge (mode, e, fallthru))
{
changed = true;
- nexte = bb->pred;
+ ix = 0;
+ ev = bb;
continue;
}
}
can eliminate redundant checks of crossjump(A,B) by arbitrarily
choosing to do the check from the block for which the edge
in question is the first successor of A. */
- if (e->src->succ != e)
+ if (EDGE_SUCC (e->src, 0) != e)
continue;
- for (e2 = bb->pred; e2; e2 = nexte2)
+ for (ix2 = 0, ev2 = bb; ix2 < EDGE_COUNT (ev2->preds); )
{
- nexte2 = e2->pred_next;
+ e2 = EDGE_PRED (ev2, ix2);
+ ix2++;
if (e2 == e)
continue;
if (try_crossjump_to_edge (mode, e, e2))
{
changed = true;
- nexte = bb->pred;
+ ev2 = bb;
+ ix = 0;
break;
}
}
if (mode & (CLEANUP_UPDATE_LIFE | CLEANUP_CROSSJUMP | CLEANUP_THREADING))
clear_bb_flags ();
- if (! (* targetm.cannot_modify_jumps_p) ())
+ if (! targetm.cannot_modify_jumps_p ())
{
first_pass = true;
/* Attempt to merge blocks as made possible by edge removal. If
changed = false;
iterations++;
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"\n\ntry_optimize_cfg iteration %i\n\n",
iterations);
bool changed_here = false;
/* Delete trivially dead basic blocks. */
- while (b->pred == NULL)
+ while (EDGE_COUNT (b->preds) == 0)
{
c = b->prev_bb;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Deleting block %i.\n",
+ if (dump_file)
+ fprintf (dump_file, "Deleting block %i.\n",
b->index);
delete_basic_block (b);
b = c;
}
- /* Remove code labels no longer used. Don't do this
- before CALL_PLACEHOLDER is removed, as some branches
- may be hidden within. */
- if (b->pred->pred_next == NULL
- && (b->pred->flags & EDGE_FALLTHRU)
- && !(b->pred->flags & EDGE_COMPLEX)
- && GET_CODE (BB_HEAD (b)) == CODE_LABEL
- && (!(mode & CLEANUP_PRE_SIBCALL)
- || !tail_recursion_label_p (BB_HEAD (b)))
+ /* Remove code labels no longer used. */
+ if (single_pred_p (b)
+ && (single_pred_edge (b)->flags & EDGE_FALLTHRU)
+ && !(single_pred_edge (b)->flags & EDGE_COMPLEX)
+ && LABEL_P (BB_HEAD (b))
/* If the previous block ends with a branch to this
block, we can't delete the label. Normally this
is a condjump that is yet to be simplified, but
if CASE_DROPS_THRU, this can be a tablejump with
some element going to the same place as the
default (fallthru). */
- && (b->pred->src == ENTRY_BLOCK_PTR
- || GET_CODE (BB_END (b->pred->src)) != JUMP_INSN
+ && (single_pred (b) == ENTRY_BLOCK_PTR
+ || !JUMP_P (BB_END (single_pred (b)))
|| ! label_is_jump_target_p (BB_HEAD (b),
- BB_END (b->pred->src))))
+ BB_END (single_pred (b)))))
{
rtx label = BB_HEAD (b);
reorder_insns_nobb (label, label, bb_note);
BB_HEAD (b) = bb_note;
}
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Deleted label in block %i.\n",
+ if (dump_file)
+ fprintf (dump_file, "Deleted label in block %i.\n",
b->index);
}
/* If we fall through an empty block, we can remove it. */
if (!(mode & CLEANUP_CFGLAYOUT)
- && b->pred->pred_next == NULL
- && (b->pred->flags & EDGE_FALLTHRU)
- && GET_CODE (BB_HEAD (b)) != CODE_LABEL
+ && single_pred_p (b)
+ && (single_pred_edge (b)->flags & EDGE_FALLTHRU)
+ && !LABEL_P (BB_HEAD (b))
&& FORWARDER_BLOCK_P (b)
/* Note that forwarder_block_p true ensures that
there is a successor for this block. */
- && (b->succ->flags & EDGE_FALLTHRU)
+ && (single_succ_edge (b)->flags & EDGE_FALLTHRU)
&& n_basic_blocks > 1)
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Deleting fallthru block %i.\n",
b->index);
c = b->prev_bb == ENTRY_BLOCK_PTR ? b->next_bb : b->prev_bb;
- redirect_edge_succ_nodup (b->pred, b->succ->dest);
+ redirect_edge_succ_nodup (single_pred_edge (b),
+ single_succ (b));
delete_basic_block (b);
changed = true;
b = c;
}
- if ((s = b->succ) != NULL
- && s->succ_next == NULL
+ if (single_succ_p (b)
+ && (s = single_succ_edge (b))
&& !(s->flags & EDGE_COMPLEX)
&& (c = s->dest) != EXIT_BLOCK_PTR
- && c->pred->pred_next == NULL
+ && single_pred_p (c)
&& b != c)
{
/* When not in cfg_layout mode use code aware of reordering
else if (!(mode & CLEANUP_CFGLAYOUT)
/* If the jump insn has side effects,
we can't kill the edge. */
- && (GET_CODE (BB_END (b)) != JUMP_INSN
+ && (!JUMP_P (BB_END (b))
|| (reload_completed
? simplejump_p (BB_END (b))
- : onlyjump_p (BB_END (b))))
+ : (onlyjump_p (BB_END (b))
+ && !tablejump_p (BB_END (b),
+ NULL, NULL))))
&& (next = merge_blocks_move (s, b, c, mode)))
{
b = next;
non-trivial jump instruction without side-effects, we
can either delete the jump entirely, or replace it
with a simple unconditional jump. */
- if (b->succ
- && ! b->succ->succ_next
- && b->succ->dest != EXIT_BLOCK_PTR
+ if (single_succ_p (b)
+ && single_succ (b) != EXIT_BLOCK_PTR
&& onlyjump_p (BB_END (b))
- && try_redirect_by_replacing_jump (b->succ, b->succ->dest,
+ && !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX)
+ && try_redirect_by_replacing_jump (single_succ_edge (b),
+ single_succ (b),
(mode & CLEANUP_CFGLAYOUT) != 0))
{
update_forwarder_flag (b);
}
if (mode & CLEANUP_CROSSJUMP)
- remove_fake_edges ();
+ remove_fake_exit_edges ();
clear_aux_for_blocks ();
tidy_fallthru_edges ();
return changed;
}
+
+/* Merges sequential blocks if possible. */
+
+bool
+merge_seq_blocks (void)
+{
+ basic_block bb;
+ bool changed = false;
+
+ for (bb = ENTRY_BLOCK_PTR->next_bb; bb != EXIT_BLOCK_PTR; )
+ {
+ if (single_succ_p (bb)
+ && can_merge_blocks_p (bb, single_succ (bb)))
+ {
+ /* Merge the blocks and retry. */
+ merge_blocks (bb, single_succ (bb));
+ changed = true;
+ continue;
+ }
+
+ bb = bb->next_bb;
+ }
+
+ return changed;
+}
\f
/* Tidy the CFG by deleting unreachable code and whatnot. */
changed = true;
/* We've possibly created trivially dead code. Cleanup it right
now to introduce more opportunities for try_optimize_cfg. */
- if (!(mode & (CLEANUP_NO_INSN_DEL
- | CLEANUP_UPDATE_LIFE | CLEANUP_PRE_SIBCALL))
+ if (!(mode & (CLEANUP_NO_INSN_DEL | CLEANUP_UPDATE_LIFE))
&& !reload_completed)
delete_trivially_dead_insns (get_insns(), max_reg_num ());
}
? PROP_LOG_LINKS : 0)))
break;
}
- else if (!(mode & (CLEANUP_NO_INSN_DEL | CLEANUP_PRE_SIBCALL))
+ else if (!(mode & CLEANUP_NO_INSN_DEL)
&& (mode & CLEANUP_EXPENSIVE)
&& !reload_completed)
{
delete_dead_jumptables ();
}
- /* Kill the data we won't maintain. */
- free_EXPR_LIST_list (&label_value_list);
timevar_pop (TV_CLEANUP_CFG);
return changed;
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